Laryngoscopes are used to facilitate endotracheal intubation of a patient during surgery to provide a positive air passageway for the administration of anesthesia and/or for the mechanical ventilation of the lungs of the patient. In the human anatomy, the epiglottis normally overlies the glottic opening into the larynx to prevent the passage of food into the trachea during eating; therefore, in endotracheal intubation, it is necessary to displace the epiglottis from the glottic opening to permit the endotracheal air tube to be inserted into the trachea.
A laryngoscope having means for indirect illumination and visualization of the pharyngeal areas of the body is disclosed in my U.S. Pat. No. 4,086,919, the disclosure of which is hereby incorporated by reference. U.S. Pat. No. 4,086,919 discloses a laryngoscope (hereafter the "Bullard Laryngoscope") for endotracheal intubation which comprises a housing containing a working channel for containing forceps and channels containing fiber optics for lighting and viewing the internal areas of the body; and a laryngoscope blade for manipulating the epiglottis of a patient to enable viewing of a target area.
Various other laryngoscope constructions are known. Other prior art laryngoscopes have consisted of a metal blade which is supportably attached to a handle and is inserted through the mouth of the patient into the pharyngeal area to displace the tongue and epiglottis and permit direct visualization of the glottic opening through the mouth opening. Such laryngoscopes have been provided with a light source which is directed along the blade to illuminate the area beyond the distal end of the blade. Two general types of rigid blade constructions are the straight, or so called "Miller blade", and the slightly curved, or so called "Macintosh blade". Curved laryngoscope blade constructions having light means to facilitate illumination of the areas of observation are described in U.S. Pat. Nos. 3,598,113; 3,643,654; 3,766,909; and 3,771,514. The Bullard Laryngoscope improves over these prior art laryngoscopes by providing an apparatus permitting the simple and rapid visualization of a target area such as the glottis to guide the insertion of an endotracheal tube.
The technique of intubation utilizing Bullard laryngoscopes is accomplished with a direct view of the larynx using either an intubating forceps or a solid stylet rod. The oral introduction and placement of the Bullard laryngoscope in a patient is described as follows, and is the same whether the intubating forceps or the solid stylet rod is used.
The blade of the Bullard laryngoscope is inserted into the oral cavity and the laryngoscope is rotated from the horizontal to the vertical position, allowing the anatomically shaped blade to slide around the tongue. Once the laryngoscope is fully vertical, final placement is facilitated by allowing the blade to drop momentarily to the posterior pharynx of the patient. The blade is then elevated against the tongue's dorsal surface. Only minimal upward movement exerted along the axis of the laryngoscope handle is required. This upward movement will result in the blade of the Bullard laryngoscope lifting the epiglottis, providing complete visualization of the glottic opening.
Prior to insertion of the Bullard laryngoscope into the patient, the user will have loaded an endotracheal tube onto the laryngoscope by using the jaws of the intubating forceps in the working channel of the Bullard laryngoscope to grasp a Murphy eye in the endotracheal tube. The tube is brought to the patient's laryngeal entrance together with the laryngoscope by the above steps. Thereafter, the endotracheal tube is advanced by advancing the forceps towards the vocal cords until the tube is past the vocal cords. At this point the forceps are released from the endotracheal tube and the tube may be advanced in the trachea to the extent necessary. Alternatively, the endotracheal tube may be fitted over a solid stylet rod that has an end located adjacent the viewing lens of the Bullard Laryngoscope, and, using the viewing capabilities of the laryngoscope, the endotracheal tube is pushed off the solid stylet rod while the laryngoscope is removed from the patient.
However, it has been found that even with the Bullard laryngoscope, if the endotracheal tube is not properly aimed or positioned by the doctor, that it will not pass between the vocal cords in the glottic opening, potentially causing trauma, or at the least, requiring more attempts at establishing the patient's airway.
It is to be appreciated that multiple positioning and repositioning is time consuming and increases the risk of creating patient trauma and possible oxygen lack. The extra time required to replace a misplaced endotracheal tube translates into an increased operating room time and cost. It would be desirable to minimize risk by eliminating extra steps currently needed to establish an endotracheal tube as a patient's airway.
In more complex situations, i.e. where the patient's lungs are to be surveyed with a bronchoscope, or where a double lumen endotracheal tube is to be used, or where high frequency jet ventilation is needed to provide the patient with oxygen, the known Bullard laryngoscope and other known laryngoscopes do not provide a method of locating the bronchoscope and/or catheters at their desired locations. For example, with a flexible-directable bronchoscope, it is typically necessary to manually locate and feed the bronchoscope into the patient's trachea. It is to be appreciated that the bronchoscope is a delicate optical instrument that can be damaged if the patient is experiencing muscle spasms or if the doctor using the instrument does not correctly align the bronchoscope before advancing it past the vocal cords. A typical replacement cost for a damaged fiber optic cable of a flexible directable bronchoscope is at least $3000.